i am sure this has been asked quite a few times and i have not been on the site in awhile. i drive an 02 taco 4x4 3.4v6 auto with 127k miles on her. the drive is 70% highway and 30% city. question is can i use penzoil yellow for 5k miles and can i use PP for 7-8k miles under the above scenerio? i keep the air filter clean however it has been shown that tacos and 4 runners may have intake issues as far as it not being filtered (air) like it should due to the drop in filters (according to Dyson.. maintenance is a must for me so she is up to date on everything. has the formulations changed in penzoil and PP?